Authorities in London are investigating the alleged poisoning of a tennis player during last month’s championships at Wimbledon, according to media reports. British tennis player Gabriella Taylor, 18, was forced to withdraw from the tournament in the middle of a juniors quarterfinal match and wound up spending days in intensive care after being felled by a mysterious illness.

NBC News reports: “London’s Metropolitan Police confirmed Thursday that officers were investigating ‘an allegation of poisoning with intent to endanger life.'”

The police are quoted saying: “It is unknown where or when the poison was ingested. There have been no arrests and inquiries continue.”

The U.K. publication The Telegraph adds: “It was initially thought that she had contracted a virus while playing overseas, but after spending four days in intensive care, doctors eventually diagnosed a rare strain of Leptospirosis, a disease caused by a bacterium that can be transmitted through rat urine.”

Officials have reportedly been exploring the possibility that Taylor was targeted by an organized crime betting syndicate.

“But the police investigation will also raise questions over whether she could have been the subject of a malicious plot by a rival player or coach from the fiercely competitive junior circuit,” The Telegraph adds.